Variable vane stabilizer

ABSTRACT

A variable vane stabilizer is disclosed. One or more variable vane stabilizer may be interconnected between/among two or more vanes of a gas turbine engine in order to fix the angle of attack of the vanes.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of, and claims priority to, U.S.application Ser. No. 15/004,709, filed Jan. 22, 2016 and entitled“VARIABLE VANE STABLIZER” and which is hereby incorporated by referencein its entirety.

FIELD

The present disclosure relates generally to mechanisms to positionstructures within gas turbine engines and more specifically, to avariable vane stabilizer to affix the position of variable vanes.

BACKGROUND

A gas turbine engine implements rotors and stators at various positionsthroughout the engine. Frequently a gas turbine engine may share similarparts with other gas turbine engines. Moreover, some gas turbine enginesmay have vanes with variable vane angle (e.g., angle of attack of vaneairfoil relative to airflow). Some gas turbine engines may have vaneswith fixed vane angle. Moreover, further gas turbine engines may havedifferent vanes with different vane angles. Producing different vaneparts for the different scenarios is costly and hampers repair andretrofit operations.

SUMMARY

A variable vane stabilizer is disclosed. The variable vane stabilizermay include a first nearest neighbor attachment configured to connect toa first adjacent variable vane stabilizer, a second nearest neighborattachment configured to connect to a second adjacent variable vanestabilizer, a circumferential extension member disposed between thefirst nearest neighbor attachment and the second nearest neighborattachment and spacing apart the first nearest neighbor attachment andthe second nearest neighbor attachment, and a vane stem interfaceconfigured to attach the variable vane stabilizer to a vane wherein anangle of attack of the vane is fixed.

In various embodiments, the first nearest neighbor attachment mayinclude a reciprocal plane tang including a tang extendingcircumferentially outward from the variable vane stabilizer, and a slipchannel including an aperture disposed perpendicularly through the tangand configured to permit insertion of a fastener. The second nearestneighbor attachment may include a first reciprocal plane fork and asecond reciprocal plane fork extending circumferentially outward fromthe variable vane stabilizer, and a slip channel disposed through eachof the first reciprocal plane fork and the second reciprocal plane forkand including an aperture configured to permit insertion of a fastener.The vane stem interface may include an axial keyed channel extendingthrough a portion of the variable vane stabilizer and configured toreceive a portion of the vane. The vane stem interface may furtherinclude keying tangs including bosses extending inwardly toward a centerof the axial keyed channel and configured to press against a portion ofthe vane, and an expansion chamfer including a relief undercut betweenthe keying tangs and a radially outermost face of the axial keyedchannel.

In various embodiments, the first nearest neighbor attachment includesan abutment surface including a planar face of a circumferentiallyoutermost surface of the variable vane stabilizer and configured toreceive the second nearest neighbor attachment of the first adjacentvariable vane stabilizer in contact radially outward of the abutmentsurface. In various embodiments, the second nearest neighbor attachmentincludes a fastener channel extending through a distal end of thecircumferential extension member and configured to receive a fastener.The second nearest neighbor attachment may include a preload spacerradially outward of the fastener channel. Moreover, the circumferentialextension member may include a planar flex member wherein a largersurface of the planar flex member lies in a generally circumferentialplane and a smaller surface of the planar flex member lies in agenerally radial plane.

In various embodiments, the second nearest neighbor attachment includesa first reciprocal plane fork and a second reciprocal plane forkextending circumferentially outward from the variable vane stabilizer, aslip channel disposed through each of the first reciprocal plane forkand the second reciprocal plane fork and including an apertureconfigured to permit insertion of a fastener. The circumferentialextension member may include a constrained flex member including aportion of the first reciprocal plane fork and a portion of the secondreciprocal plane fork each configured to permit flexing of the variablevane stabilizer.

In various embodiments, the first nearest neighbor attachment includes aradial tab extending radially outward from the variable vane stabilizer,and a trunnion receiving bearing including a bearing disposed in anaperture through the radial tab. The second nearest neighbor attachmentmay include a radial tab extending radially outward from the variablevane stabilizer, and a trunnion including a shaft extending from theradial tab perpendicular to the radial tab and configured to be receivedin a trunnion receiving bearing of the first adjacent variable vanestabilizer.

A variable vane stabilizer may have a circumferential extension memberbounded by a first vane stem interface and a second vane stem interfacedisposed at opposite distal ends of the circumferential extensionmember. The circumferential extension member may include a planar flexmember wherein a larger surface of the planar flex member lies in agenerally circumferential plane and a smaller surface of the planar flexmember lies in a generally radial plane. Each vane stem interface mayinclude an axial keyed channel extending through a portion of thevariable vane stabilizer and configured to receive a portion of a vane.Each vane stem interface may include a circumferential keyed channelextending through a portion of the variable vane stabilizer andlongitudinally aligned along a primary axis of the variable vanestabilizer.

A method of variable vane stabilizer installation is disclosed. Themethod may include attaching a first variable vane stabilizer to a firstvane, attaching a second variable vane stabilizer to a second vaneadjacent to the first vane, attaching a third variable vane stabilizerto a third vane adjacent to the second vane, and linking the firstvariable vane stabilizer, second variable vane stabilizer, and thirdvariable vane stabilizer.

The linking may include connecting a first nearest neighbor attachmentof the first variable vane stabilizer to a second nearest neighborattachment of the second variable vane stabilizer, and connecting afirst nearest neighbor attachment of the second variable vane stabilizerto a second nearest neighbor attachment of the third variable vanestabilizer.

The first variable vane stabilizer, the second variable vane stabilizer,and the third variable vane stabilizer each may include acircumferential extension member disposed between the first nearestneighbor attachment and the second nearest neighbor attachment andspacing apart the first nearest neighbor attachment and the secondnearest neighbor attachment, and a vane stem interface configured toattach the variable vane stabilizer to a vane. In various embodiments,the first vane has a first angle of attack, the second vane has a secondangle of attack, the third vane has a third angle of attack, and thefirst, second, and third angle of attack are the same.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, is bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the drawing figures, wherein like numeralsdenote like elements.

FIG. 1 illustrates a cross-sectional view of an exemplary gas turbineengine, according to various embodiments;

FIG. 2 illustrates an example block diagram of an example variable vanestabilizer, according to various embodiments;

FIGS. 3A-B illustrate a variable vane stabilizer with a billetconfiguration, in accordance with various embodiments;

FIG. 4 illustrates a variable vane stabilizer with a fork and shoulderbolt configuration, in accordance with various embodiments;

FIG. 5 illustrates a variable vane stabilizer with a bolted clevisconfiguration, in accordance with various embodiments;

FIG. 6 illustrates a variable vane stabilizer with a trunnion shaftconfiguration, in accordance with various embodiments;

FIGS. 7A-B illustrate a variable vane stabilizer with an axial vanetrunnion configuration, in accordance with various embodiments;

FIG. 8 illustrates a variable vane stabilizer with a circumferentialvane trunnion configuration, in accordance with various embodiments;

FIG. 9 illustrates a variable vane stabilizer configured to connectthree variable vanes, in accordance with various embodiments;

FIG. 10 illustrates a method of variable vane stabilizer installation,in accordance with various embodiments.

DETAILED DESCRIPTION

The detailed description of exemplary embodiments herein makes referenceto the accompanying drawings, which show exemplary embodiments by way ofillustration. While these exemplary embodiments are described insufficient detail to enable those skilled in the art to practiceembodiments of the disclosure, it should be understood that otherembodiments may be realized and that logical changes and adaptations indesign and construction may be made in accordance with this inventionand the teachings herein. Thus, the detailed description herein ispresented for purposes of illustration only and not limitation. Thescope of the disclosure is defined by the appended claims. For example,the steps recited in any of the method or process descriptions may beexecuted in any order and are not necessarily limited to the orderpresented. Furthermore, any reference to singular includes pluralembodiments, and any reference to more than one component or step mayinclude a singular embodiment or step. Also, any reference to attached,fixed, connected or the like may include permanent, removable,temporary, partial, full and/or any other possible attachment option.Additionally, any reference to without contact (or similar phrases) mayalso include reduced contact or minimal contact.

Furthermore, any reference to singular includes plural embodiments, andany reference to more than one component or step may include a singularembodiment or step. Surface shading lines may be used throughout thefigures to denote different parts but not necessarily to denote the sameor different materials.

With reference to FIG. 1, an exemplary gas turbine engine 2 is provided.Gas turbine engine 2 is a two-spool turbofan that generally incorporatesa fan section 4, a compressor section 6, a combustor section 8 and aturbine section 10. Vanes 51 may be disposed throughout the gas turbineengine 2. Alternative engines include, for example, an augmentor sectionamong other systems or features. In operation, fan section 4 drives airalong a bypass flow-path B while compressor section 6 drives air along acore flow-path C for compression and communication into combustorsection 8 then expansion through turbine section 10. Although depictedas a turbofan gas turbine engine 2 herein, it should be understood thatthe concepts described herein are not limited to use with turbofans asthe teachings is applicable to other types of turbine engines includingthree-spool architectures. A gas turbine engine may comprise anindustrial gas turbine (IGT) or a geared aircraft engine, such as ageared turbofan, or non-geared aircraft engine, such as a turbofan, ormay comprise any gas turbine engine as desired.

Gas turbine engine 2 generally comprises a low speed spool 12 and a highspeed spool 14 mounted for rotation about an engine central longitudinalaxis X-X′ relative to an engine static structure 16 via several bearingsystems 18-1, 18-2, and 18-3. It should be understood that bearingsystems may alternatively and/or additionally be provided at variouslocations, including for example, bearing system 18-1, bearing system18-2, and bearing system 18-3.

Low speed spool 12 generally comprises an inner shaft 20 thatinterconnects a fan 22, a low pressure compressor section 24, e.g., afirst compressor section, and a low pressure turbine section 26, e.g., asecond turbine section. Inner shaft 20 is connected to fan 22 through ageared architecture 28 that drives the fan 22 at a lower speed than lowspeed spool 12. Geared architecture 28 comprises a gear assembly 42enclosed within a gear housing 44. Gear assembly 42 couples the innershaft 20 to a rotating fan structure. High speed spool 14 comprises anouter shaft 30 that interconnects a high pressure compressor section 32,e.g., second compressor section, and high pressure turbine section 34,e.g., first turbine section. A combustor 36 is located between highpressure compressor section 32 and high pressure turbine section 34. Amid-turbine frame 38 of engine static structure 16 is located generallybetween high pressure turbine section 34 and low pressure turbinesection 26. Mid-turbine frame 38 supports one or more bearing systems18, such as 18-3, in turbine section 10. Inner shaft 20 and outer shaft30 are concentric and rotate via bearing systems 18 about the enginecentral longitudinal axis X-X′, which is collinear with theirlongitudinal axes. As used herein, a “high pressure” compressor orturbine experiences a higher pressure than a corresponding “lowpressure” compressor or turbine.

The core airflow C is compressed by low pressure compressor section 24then high pressure compressor section 32, mixed and burned with fuel incombustor 36, then expanded over high pressure turbine section 34 andlow pressure turbine section 26. Mid-turbine frame 38 includes surfacestructures 40, which are in the core airflow path. Turbines 26, 34rotationally drive the respective low speed spool 12 and high speedspool 14 in response to the expansion.

Gas turbine engine 2 is, for example, a high-bypass geared aircraftengine. The bypass ratio of gas turbine engine 2 is optionally greaterthan about six (6). The bypass ratio of gas turbine engine 2 isoptionally greater than ten (10). Geared architecture 28 is an epicyclicgear train, such as a star gear system, e.g., sun gear in meshingengagement with a plurality of star gears supported by a carrier and inmeshing engagement with a ring gear, or other gear system. Gearedarchitecture 28 has a gear reduction ratio of greater than about 2.3 andlow pressure turbine section 26 has a pressure ratio that is greaterthan about five (5). The bypass ratio of gas turbine engine 2 is greaterthan about ten (10:1). The diameter of fan 22 is significantly largerthan that of the low pressure compressor section 24, and the lowpressure turbine section 26 has a pressure ratio that is greater thanabout 5:1. Low pressure turbine section 26 pressure ratio is measuredprior to inlet of low pressure turbine section 26 as related to thepressure at the outlet of low pressure turbine section 26 prior to anexhaust nozzle. It should be understood, however, that the aboveparameters are exemplary of a suitable geared architecture engine andthat the present disclosure contemplates other turbine engines includingdirect drive turbofans.

An engine 2 may comprise a rotor blade 68 or a stator vane 51. Statorvanes 51 may be arranged circumferentially about the engine centrallongitudinal axis X-X′. Stator vanes 51 may be variable, meaning theangle of attack of the airfoil of the stator vane may be variablerelative to the airflow proximate to the stator vanes 51. The angle ofattack of the variable stator vane 51 may be variable during operation,or may be fixable for operation, for instance, being variable duringmaintenance or construction and fixable for operation. In variousembodiments, it may be desirable to affix a variable vane 51 in fixedposition (e.g., constant angle of attack).

With reference to FIG. 2, a block diagram of a variable vane stabilizer50A, 50B, 50C, 50D, 50E, 50F is disclosed. As will be discussed furtherherein, a variable vane stabilizer may be interconnected between/amongtwo or more vanes in order to fix the angle of attack of the vanes.While various embodiments will be discussed herein, and the discussionof various aspects of variable vane stabilizers may be limited tospecific embodiments for brevity, features of different embodiments arenot limited to the specifically indicated embodiments, but may becombined with features of other embodiments in various combinations. Forinstance, aspects of a variable vane stabilizer 50A may be combined withaspects of a variable vane stabilizer 50B. As used herein, like numeralsmay denote like features. For instance, while FIG. 3A depicts aplurality of variable vane stabilizers 50A interconnected in combinationwith vanes 51, any variable vane stabilizer 50A, 50B, 50C, 50D, 50E, 50Fmay be similarly situated.

A variable vane stabilizer 50A, 50B, 50C, 50D, 50E, 50F may include afirst nearest neighbor attachment 100A, 100B, 100C, 100D, 100E, or 100F,respectively. Adjacent variable vane stabilizers may be desired to beinterconnected. Thus, a variable vane stabilizer may also have a secondnearest neighbor attachment 400A, 400B, 400C, 400D, 400E, 400Fconfigured to interconnect to a first nearest neighbor attachment 100A,100B, 100C, 100D, 100E, or 100F of an adjacent neighbor. A variable vanestabilizer 50A, 50B, 50C, 50D, 50E, 50F may include a vane steminterface 300A, 300B, 300C, 300D, 300E, 300F configured to join thevariable vane stabilizer to a vane 51, wherein the angle of attack ofthe vane is fixed. Finally, a variable vane stabilizer 50A, 50B, 50C,50D, 50E, 50F may have a circumferential extension member 200A, 200B,200C, 200D, 200E, 200F. The circumferential extension member 200A, 200B,200C, 200D, 200E, 200F may be disposed between the first and secondnearest neighbor attachments and may extend generally circumferentiallyrelative to the engine central longitudinal axis X-X′ in order to spaceapart the first nearest neighbor attachment and the second nearestneighbor attachment, whereby the adjacent variable vane stabilizers maybe joined in a generally annular arrangement. The circumferentialextension member may be configured to flex so that the otherwisegenerally linear variable vane stabilizers may be arranged generallyannularly.

A variable vane stabilizer thus may perform several functions. Forinstance, a variable vane stabilizer may lock two or more adjacent vanestogether, fixing their individual angles of attack using existingfeatures of the vanes. Moreover, the variable vane stabilizer addressesthe challenge associated with the variable spacing between the vanes dueto being located in a split case of a gas turbine engine. As will bediscussed further herein, various aspects of the variable vanestabilizers may be associated with preloading. For instance, to providesystem damping, adjacent variable vane stabilizers may be preloadedagainst preload spacers, allowing thermal growth in the system.

Generally, the variable vane stabilizers may be installed as follows. Avariable vane stabilizer may be attached to a first vane with the firstblade angle of attack positioned such that it aligns with an adjacentblade. The variable vane stabilizers of the first vane and the secondvane may then be linked. This may be repeated for each variable vane,and finally the fasteners for each variable vane stabilizer are insertedand tightened, preloading the annular arrangement of adjacent variablevane stabilizers.

Billet Variable Vane Stabilizer

With reference to FIG. 3B, a billet variable vane stabilizer 50A isdisclosed. A billet variable vane stabilizer 50A may comprise a firstnearest neighbor attachment 100A, a circumferential extension member200A, a vane stem interface 300A, and a second nearest neighborattachment 400A.

The first nearest neighbor attachment 100A may comprise a reciprocalplane tang 101. A reciprocal plane tang 101 may comprise a tangextending circumferentially outward from a billet variable vanestabilizer 50A. The first nearest neighbor attachment 100A may alsoinclude a slip channel 103 comprising an aperture disposedperpendicularly through the tang (e.g., aligned to permit insertion of afastener parallel with the engine central longitudinal axis X-X′).

The second nearest neighbor attachment 400A may comprise reciprocalplane forks 401. In various embodiments, two reciprocal plane forks 401(a first reciprocal plane fork 401 and a second reciprocal plane fork401) extend circumferentially outward from a billet variable vanestabilizer 50A in a direction opposite to the reciprocal plane tang 101.The reciprocal plane forks 401 may be spaced apart so that a reciprocalplane tang 101 of an adjacent billet variable vane stabilizer 50A may beinsertable between the reciprocal plane forks 401. A slip channel 403may be disposed through each reciprocal plane fork 401 and positioned sothat a fastener may be inserted through each reciprocal plane fork 401and the reciprocal plane tang 101 of an adjacent billet variable vanestabilizer 50A. In this manner, adjacent billet variable vanestabilizers 50A may be interconnected. Moreover, the slip channel 403and/or the slip channel 103 may comprise a channel having a length thatis longer than a width, the length extending in a generallycircumferential direction relative to the engine central longitudinalaxis X-X′. In this manner, the billet variable vane stabilizers 50A maybe configured to permit relative motion of the adjacent billet variablevane stabilizers 50A in a single degree of freedom (e.g.,circumferential growth, and/or corresponding radial growth, and/or suchas to accommodate thermal effects and to accommodate an angle betweenthe vanes resulting from the annular arrangement of the vanes) whileprecluding twisting. A vane 51 may be attached to each vane steminterface 300A so that in this manner twisting of the vanes 51 isconstrained, whereas circumferential or radial motion of the vanes 51,such as in response to differential coefficients of thermal expansion,may be permitted.

The vane stem interface 300A may comprise an axial keyed channel 301. Anaxial keyed channel 301 may comprise a channel extending through aportion of the billet variable vane stabilizer 50A and parallel to theengine central longitudinal axis X-X′ (as opposed to lying in acircumferential plane). A vane 51 may be received into the axial keyedchannel 301 and affixed in positon by a fastener, such as may beinsertable through a fastener aperture 304 of the vane stem interface300A.

The circumferential extension member 200A may comprise a constrainedflex member 201. A constrained flex member 201 may permit limitedflexing of the billet variable vane stabilizer 50A in one or moredegree(s) of freedom, such as to accommodate thermal effects and toaccommodate an angle between the vanes (for instance, an angle resultingfrom the annular arrangement of the vanes), and may limit flexing of thebillet variable vane stabilizer 50A in one or more other degrees offreedom. For instance, as depicted in FIG. 3B, the circumferentialextension member 200A is a portion of the reciprocal plane forks 401, sothat movement in a radial direction is constrained. Thus, thecircumferential extension member 200A and the relationship of the slipchannels 103, 403, may combine to permit limited movement in acircumferential direction, while limiting movement in other directions.

Fork and Shoulder Variable Vane Stabilizer

With reference to FIG. 4, a fork and shoulder variable vane stabilizer50B is disclosed. A fork and shoulder variable vane stabilizer 50B maybe configured to exhibit various characteristics, for instance, such anarrangement further accommodates tolerance stack up during assembly andthermal growth. Flexibility is sufficient for vibration damping and invarious embodiments, no modification to a vane trunnion to vane steminterface 300B would be implemented, enhancing retrofit installations. Afork and shoulder variable vane stabilizer 50B may comprise a firstnearest neighbor attachment 100B, a circumferential extension member200B, a vane stem interface 300B, and a second nearest neighborattachment 400B.

The first nearest neighbor attachment 100B may comprise an abutmentsurface 105. An abutment surface 105 may comprise a planar face of acircumferentially outermost surface of the fork and shoulder variablevane stabilizer 50B (e.g., a shoulder). The abutment surface 105 may bepositioned so that a second nearest neighbor attachment 400B of anadjacent fork and shoulder variable vane stabilizer 50B may rest atop(circumferentially outboard of) the abutment surface 105.

The second nearest neighbor attachment 400B may comprise a fastenerchannel 405 extending through a distal end of the circumferentialextension member 200B of an adjacent fork and shoulder variable vanestabilizer 50B. The fastener channel 405 may be configured to receive afastener inserted in a radial direction through the fastener channel 405and into an aperture in the abutment surface 105 of the adjacent forkand shoulder variable vane stabilizer. The fastener may extend into aportion of a vane 51, whereby the fork and shoulder variable vanestabilizer may be connected to the vane. In various embodiments, thesecond nearest neighbor attachment 400B further comprises a preloadspacer 407, disposed radially outward of the fastener channel 405 andconfigured to interoperate with a fastener 457 to exert a preload on thefork and shoulder variable vane stabilizer 50B and to dampen movement ofthe fork and shoulder variable vane stabilizer 50B.

The circumferential extension member 200B may comprise a planar flexmember 203. The planar flex member 203 may comprise a planar memberlying in a generally circumferential plane, wherein a larger surface ofthe planar member lies in the generally circumferential plane (e.g.,forming an partially annular section) and wherein a smaller surface ofthe planar member lies in a generally radial plane (e.g., forming aplane in which a radial line extending from the engine centrallongitudinal axis X-X′ lies). In this manner, planar flex member 203 maybe configured to permit the relative motion of adjacent fork andshoulder variable vane stabilizers 50B in some degrees of freedom, butnot others (for instance, circumferential growth, and/or correspondingradial growth) while precluding twisting. A vane 51 may be attached toeach vane stem interface 300B so that in this manner twisting of thevanes 51 is constrained, whereas circumferential or radial motion of thevanes 51, such as in response to differential coefficients of thermalexpansion, may be permitted.

The vane stem interface 300B may comprise an axial keyed channel 301. Anaxial keyed channel 301 may comprise a channel extending through aportion of the fork and shoulder variable vane stabilizers 50B andparallel to the engine central longitudinal axis X-X′ (as opposed tolying in a circumferential plane). A vane 51 may be received into theaxial keyed channel 301 and affixed in positon by a fastener, such asmay be insertable through a fastener aperture of the vane stem interface300B. In various embodiments, this fastener aperture is the fastenerchannel 405. The vane stem interface 300B may comprise keying tangs 303and an expansion chamfer 305. Keying tangs 303 may comprise bossesextending inwardly toward the center of the axial keyed channel 301 andconfigured to press against a portion of the vane 51 such as a vanestem. The expansion chamfer 305 may comprise a relief undercut betweeneach keying tang and the floor (e.g., radially outermost face) of theaxial keyed channel 301. In this manner, thermal expansion of aspects ofthe vane and the bolted clevis variable vane stabilizer 50B may becompensated, such as in response to preloading the keying tangs 303against the portion of the vane 51 such as the vane stem.

Bolted Clevis Variable Vane Stabilizer

With reference to FIG. 5, a bolted clevis variable vane stabilizer 50Cis disclosed. A bolted clevis variable vane stabilizer 50C may beconfigured to exhibit various characteristics, for instance, such anarrangement further accommodates tolerance stack up during assembly andthermal growth. Flexibility is sufficient for vibration damping and invarious embodiments, no modification to a vane trunnion to vane steminterface 300C would be implemented, enhancing retrofit installations. Abolted clevis variable vane stabilizer 50C may comprise a first nearestneighbor attachment 100C, a circumferential extension member 200C, avane stem interface 300C, and a second nearest neighbor attachment 400C.

The first nearest neighbor attachment 100C may comprise a reciprocalplane tang 101. A reciprocal plane tang 101 may comprise a tangextending circumferentially outward from a bolted clevis variable vanestabilizer 50C. A slip channel 103 may comprise an aperture disposedperpendicularly through the tang (e.g., aligned to permit insertion of afastener parallel with the engine central longitudinal axis X-X′).

The second nearest neighbor attachment 400C may comprise one or morereciprocal plane forks 401. In various embodiments, two reciprocal planeforks 401 extend circumferentially outward from a bolted clevis variablevane stabilizer 50C in a direction opposite to the reciprocal plane tang101. The reciprocal plane forks 401 may be spaced apart so that areciprocal plane tang 101 of an adjacent bolted clevis variable vanestabilizer 50C may be insertable between the reciprocal plane forks 401.A slip channel 403 may be disposed through each reciprocal plane fork401 and positioned so that a fastener may be inserted through eachreciprocal plane fork 401 and the reciprocal plane tang 101 of anadjacent bolted clevis variable vane stabilizer 50C. In this manner,adjacent bolted clevis variable vane stabilizer 50C may beinterconnected. Moreover, the slip channel 403 and/or the slip channel103 may comprise a channel having a length that is longer than a width,the length extending in a generally circumferential direction relativeto the engine central longitudinal axis X-X′. In this manner, the boltedclevis variable vane stabilizer 50C may be configured to permit relativemotion of the adjacent bolted clevis variable vane stabilizer 50C in asingle degree of freedom (e.g., circumferential growth, and/orcorresponding radial growth, and/or such as to accommodate thermaleffects and to accommodate an angle between the vanes resulting from theannular arrangement of the vanes) while precluding twisting. A vane 51may be attached to each vane stem interface 300C so that in this mannertwisting of the vanes 51 is constrained, whereas circumferential orradial motion of the vanes 51, such as in response to differentialcoefficients of thermal expansion, may be permitted.

The vane stem interface 300C may comprise an axial keyed channel 301. Anaxial keyed channel 301 may comprise a channel extending through aportion of the bolted clevis variable vane stabilizer 50C and parallelto the engine central longitudinal axis X-X′ (as opposed to lying in acircumferential plane). A vane 51 may be received into the axial keyedchannel 301 and affixed in positon by a fastener, such as may beinsertable through a fastener aperture of the vane stem interface 300C.The vane stem interface 300C may comprise keying tangs 303 and anexpansion chamfer 305. Keying tangs 303 may comprise bosses extendinginwardly toward the center of the axial keyed channel 301 and configuredto press against a portion of the vane 51 such as a vane stem. Theexpansion chamfer 305 may comprise a relief undercut between each keyingtang and the floor (e.g., radially outermost face) of the axial keyedchannel 301. In this manner, thermal expansion of aspects of the vaneand the bolted clevis variable vane stabilizer 50C may be compensated,such as in response to preloading the keying tangs 303 against theportion of the vane 51 such as the vane stem.

The circumferential extension member 200C may comprise a constrainedflex member 201. A constrained flex member 201 may permit limitedflexing of the bolted clevis variable vane stabilizer 50C in one or moredegree(s) of freedom, and may limit flexing of the bolted clevisvariable vane stabilizer 50C in one or more other degree(s) of freedom.For instance, the circumferential extension member 200C is a portion ofthe reciprocal plane forks 401, so that movement in a radial directionis constrained. Thus, the circumferential extension member 200C and therelationship of the slip channels 103, 403, may combine to permitlimited movement in a circumferential direction, while limiting movementin other directions.

Trunnion Shaft Variable Vane Stabilizer

With reference to FIG. 6, a trunnion shaft variable vane stabilizer 50Dis disclosed. A trunnion shaft variable vane stabilizer 50D may beconfigured to exhibit various characteristics, for instance, such anarrangement further accommodates tolerance stack up during assembly andthermal growth. Flexibility is sufficient for vibration damping and invarious embodiments, no modification to a vane trunnion to vane steminterface 300D would be implemented, enhancing retrofit installations. Atrunnion shaft variable vane stabilizer 50D may comprise a first nearestneighbor attachment 100D, a circumferential extension member 200D, avane stem interface 300D, and a second nearest neighbor attachment 400D.

The first nearest neighbor attachment 100D may comprise a radial tab109. A radial tab may comprise a tab that extends radially outward fromthe trunnion shaft variable vane stabilizer 50D relative to the enginecentral longitudinal axis X-X′. The first nearest neighbor attachment100D may be disposed at a distal end of the trunnion shaft variable vanestabilizer 50D. Similarly, a second nearest neighbor attachment 400D maybe disposed at the opposite distal end of the trunnion shaft variablevane stabilizer 50D and may similarly comprise a radial tab 109. Thus, atrunnion shaft variable vane stabilizer 50D may have a radial tab 109 ateach distal end (e.g., the circumferentially outermost ends of thetrunnion shaft variable vane stabilizer 50D relative to the enginecentral longitudinal axis X-X′).

The first nearest neighbor attachment 100D may comprise a trunnionreceiving bearing 111. A trunnion receiving bearing 111 may comprise abearing disposed in an aperture through the radial tab 109.

The second nearest neighbor attachment 400D may further comprise atrunnion 409. The trunnion 409 may comprise a shaft extending generallyoutward from the radial tab 109 and perpendicular to the radial tab 109.

Thus, one may appreciate that the trunnion receiving bearing 111 mayreceive the trunnion 409 of an adjacent trunnion shaft variable vanestabilizer 50D. In this manner, the trunnion shaft variable vanestabilizers 50D may be configured to permit relative motion of theadjacent trunnion shaft variable vane stabilizers 50D in a single degreeof freedom (e.g., circumferential growth, and/or corresponding radialgrowth, and/or such as to accommodate thermal effects and to accommodatean angle between the vanes resulting from the annular arrangement of thevanes) while precluding twisting. A vane 51 may be attached to each vanestem interface 300D so that in this manner twisting of the vanes 51 isconstrained, whereas circumferential or radial motion of the vanes 51,such as in response to differential coefficients of thermal expansion,may be permitted.

The vane stem interface 300D may comprise an axial keyed channel 301. Anaxial keyed channel 301 may comprise a channel extending through aportion of the trunnion shaft variable vane stabilizers 50D and parallelto the engine central longitudinal axis X-X′ (as opposed to lying in acircumferential plane). A vane 51 may be received into the axial keyedchannel 301 and affixed in position by a fastener, such as may beinsertable through a fastener aperture of the vane stem interface 300D.

The circumferential extension member 200D may comprise a planar flexmember 203. A planar flex member 203 may permit limited flexing of thetrunnion shaft variable vane stabilizer 50D in one or more degree(s) offreedom, and may limit flexing of the trunnion shaft variable vanestabilizer 50D in one or more other degree(s) of freedom. Thus, thecircumferential extension member 200D and the relationship of thetrunnion 409 and trunnion receiving bearing 111 may combine to permitlimited movement in a circumferential direction, while limiting movementin other directions.

Axial Vane Trunnion Variable Vane Stabilizer

With reference to FIG. 7A-B, an axial vane trunnion variable vanestabilizer 50E is disclosed. An axial vane trunnion variable vanestabilizer 50E may comprise a circumferential extension member 200Ebounded at each distal end by a vane stem interface 300E. Thus, one mayappreciate that the nearest neighbor attachments 100E, 400E may beomitted and first and second vane stem interfaces 300E may bound thecircumferential extension member 200E.

A circumferential extension member 200E may comprise a planar flexmember 203. A planar flex member 203 may permit limited flexing of theaxial vane trunnion variable vane stabilizer 50E in one or moredegree(s) of freedom, and may limit flexing of the axial vane trunnionvariable vane stabilizer 50E in one or more other degree(s) of freedom.Thus, the circumferential extension member 200E and the two vane steminterfaces 300E may combine to permit limited movement in acircumferential direction, while limiting movement in other directions.

Each vane stem interface 300E may comprise an axial keyed channel 301.An axial keyed channel 301 may comprise a channel extending through aportion of the axial vane trunnion variable vane stabilizer 50E andparallel to the engine central longitudinal axis X-X′ (as opposed tolying in a circumferential plane). A vane 51 may be received into theaxial keyed channel 301 and affixed in position by a fastener, such asmay be insertable through a fastener aperture of the vane stem interface300E.

Circumferential Vane Trunnion Variable Vane Stabilizer

With reference to FIG. 8, a circumferential vane trunnion variable vanestabilizer 50F is disclosed. A circumferential vane trunnion variablevane stabilizer 50F may be configured to exhibit variouscharacteristics, for instance, such an arrangement further accommodatestolerance stack up during assembly and thermal growth. Flexibility maybe sufficient for vibration damping, although stiffness may also beaccommodated, as the circumferential orientation of the circumferentialkeyed channel(s) 309 accommodate circumferential movement andvariations. Moreover, as depicted in FIG. 9, while various embodimentsdisclosed herein may be extended to accommodate more than two vanes fora single variable vane stabilizer, the circumferential vane trunnionvariable vane stabilizer 50F is specifically illustrated in FIG. 9accommodating three vanes, such as may be desired to accommodate oddnumbers of vanes.

A circumferential vane trunnion variable vane stabilizer 50F maycomprise a circumferential extension member 200F bounded at each distalend by a vane stem interface 300F. Thus, one may appreciate that thenearest neighbor attachments 100F, 400F may be omitted. Thus, one mayappreciate that the nearest neighbor attachments 100F, 400F may beomitted and first and second vane stem interfaces 300F may bound thecircumferential extension member 200F

With reference to FIG. 8, a circumferential extension member 200F maycomprise a planar flex member 203. A planar flex member 203 may permitlimited flexing of the circumferential vane trunnion variable vanestabilizer 50F in one or more degree(s) of freedom, and may limitflexing of the circumferential vane trunnion variable vane stabilizer50F in one or more other degree(s) of freedom. Thus, the circumferentialextension member 200F and the two vane stem interfaces 300F may combineto permit limited movement in a circumferential direction, whilelimiting movement in other directions.

Each vane stem interface 300F may comprise a circumferential keyedchannel 309. The circumferential keyed channel 309 may comprise achannel extending through a portion of the circumferential vane trunnionvariable vane stabilizer 50F perpendicularly to a longer surface of thecircumferential vane trunnion variable vane stabilizer 50F and parallelto a shorter surface of the circumferential vane trunnion variable vanestabilizer 50F (e.g., longitudinally aligned along a primary axis of thecircumferential vane trunnion variable vane stabilizer 50F). Thecircumferentially keyed channel 309 may be perpendicular to the enginecentral longitudinal axis X-X′. A vane 51 may be received into thecircumferential keyed channel 309 and affixed in position by a fastener,such as may be insertable through a fastener aperture of the vane steminterface 300F.

Having discussed different structural aspects of variable vanestabilizers, attention is directed to FIG. 10, which discloses a methodof variable vane stabilizer installation 1000. The method may includeattaching a first variable vane stabilizer to a first vane (step 1001),attaching a second variable vane stabilizer to a second vane adjacent tothe first vane (step 1003), attaching a third variable vane stabilizerto a third vane adjacent to the second vane (step 1005), and linking thefirst variable vane stabilizer, second variable vane stabilizer, andthird variable vane stabilizer (step 1007). The linking may includeconnecting a first nearest neighbor attachment of the first variablevane stabilizer to a second nearest neighbor attachment of the secondvariable vane stabilizer and connecting a first nearest neighborattachment of the second variable vane stabilizer to a second nearestneighbor attachment of the third variable vane stabilizer. In variousembodiments, the first vane has a first angle of attack, the second vanehas a second angle of attack, and the third vane has a third angle ofattack. By linking the variable vane stabilizers, these angles of attackmay be fixed. In various embodiments, the first, second, and third angleof attack are the same. The assembly of nearest neighbor attachments maybe secured in connection to each other and the assembly may be repeatedto form a complete annulus of variable vane stabilizers. Finally,fasteners may be inserted through slip channels of the nearest neighborattachments (step 1009), whereby the assembly of nearest neighborattachments may be secured in connection to each other preloading theannular arrangement of adjacent variable vane stabilizers.

With reference to FIGS. 1-9, a variable vane stabilizer 50A, 50B, 50C,50D, 50E, and 50F, may be made of various materials. For instance, avariable vane stabilizer 50A, 50B, 50C, 50D, 50E, and 50F may be made ofa single material, or different materials, or combinations of materials.For example, components of the system are made from metal. For example,aspects of a variable vane stabilizer 50A, 50B, 50C, 50D, 50E, and 50Fare metal, such as nickel, cobalt, molybdenum, titanium, aluminum,steel, or stainless steel, though it alternatively comprises numerousother materials configured to provide support. Components of the systemare optionally made from other materials such as, for example,composite, ceramic, plastics, polymers, alloys, glass, binder, epoxy,polyester, acrylic, or any material or combination of materials havingdesired material properties, such as heat tolerance, strength,stiffness, or weight. Portions of a variable vane stabilizer 50A, 50B,50C, 50D, 50E, and 50F as disclosed herein are optionally made ofdifferent materials or combinations of materials, and/or comprisecoatings. Moreover, components of the variable vane stabilizer 50A, 50B,50C, 50D, 50E, and 50F are in some instances mixtures of differentmaterials according to different ratios, gradients, and the like.

A variable vane stabilizer 50A, 50B, 50C, 50D, 50E, and 50F thus hasmultiple materials, or any material configuration suitable to enhance orreinforce the resiliency and/or support of the system when subjected towear in an aircraft or industrial operating environment or to satisfyother desired electromagnetic, chemical, physical, or materialproperties, for example coefficient of thermal expansion, ductility,weight, flexibility, strength, or heat tolerance.

One such material is an austenitic nickel-chromium-based alloy such asInconel®, which is available from Special Metals Corporation of NewHartford, N.Y., USA. Other such material includes ceramic matrixcomposite (CMC). Further material includes refractory metal, forexample, an alloy of titanium, such as, titanium-zirconium-molybdenum(TZM).

Various benefits and advantages have been described herein with regardto specific embodiments. Furthermore, the connecting lines shown in thevarious figures contained herein are intended to represent exemplaryfunctional relationships and/or physical couplings between the variouselements. It should be noted that many alternative or additionalfunctional relationships or physical connections may be present in apractical system. However, the benefits, advantages, and any elementsthat may cause any benefit or advantage to occur or become morepronounced are not to be construed as critical, required, or essentialfeatures or elements of the disclosure. The scope of the disclosure isaccordingly to be limited by nothing other than the appended claims, inwhich reference to an element in the singular is not intended to mean“one and only one” unless explicitly so stated, but rather “one ormore.” Moreover, where a phrase similar to “at least one of A, B, or C”is used in the claims, it is intended that the phrase be interpreted tomean that A alone may be present in an embodiment, B alone may bepresent in an embodiment, C alone may be present in an embodiment, orthat any combination of the elements A, B and C may be present in asingle embodiment; for example, A and B, A and C, B and C, or A and Band C.

The foregoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated otherwise.These features and elements as well as the operation thereof will becomemore apparent in light of the following description and the accompanyingdrawings. It should be understood, however, the following descriptionand drawings are intended to be exemplary in nature and non-limiting.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “various embodiments”, “oneembodiment”, “an embodiment”, “an example embodiment”, etc., indicatethat the embodiment described may include a particular feature,structure, or characteristic, but every embodiment may not necessarilyinclude the particular feature, structure, or characteristic. Moreover,such phrases are not necessarily referring to the same embodiment.Further, when a particular feature, structure, or characteristic isdescribed in connection with an embodiment, it is submitted that it iswithin the knowledge of one skilled in the art to affect such feature,structure, or characteristic in connection with other embodimentswhether or not explicitly described. After reading the description, itwill be apparent to one skilled in the relevant art(s) how to implementthe disclosure in alternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element herein is to be construed under theprovisions of 35 U.S.C. 112(f), unless the element is expressly recitedusing the phrase “means for.” As used herein, the terms “comprises”,“comprising”, or any other variation thereof, are intended to cover anon-exclusive inclusion, such that a process, method, article, orapparatus that comprises a list of elements does not include only thoseelements but may include other elements not expressly listed or inherentto such process, method, article, or apparatus.

The invention claimed is:
 1. A variable vane stabilizer comprising: afirst nearest neighbor attachment comprising a channel and configured toconnect to a first adjacent variable vane stabilizer in accordance withthe variable vane stabilizer; a second nearest neighbor attachmentconfigured to connect to a second adjacent variable vane stabilizer inaccordance with the variable vane stabilizer; a circumferentialextension member disposed between the first nearest neighbor attachmentand the second nearest neighbor attachment and spacing apart the firstnearest neighbor attachment and the second nearest neighbor attachment,the second nearest neighbor attachment comprising a fastener channelextending through a distal end of the circumferential extension memberand configured to receive a fastener; and a vane stem interfaceconfigured to attach the variable vane stabilizer to a vane with a fixedangle of attack, wherein: the first nearest neighbor attachment furthercomprises an abutment surface, the abutment surface includes a planarface disposed circumferentially outboard of the vane stem interface, theabutment surface is configured to contact a third nearest neighborattachment of the second adjacent variable vane stabilizer, the thirdnearest neighbor attachment is in accordance with the second nearestneighbor attachment of the variable vane stabilizer, and the thirdnearest neighbor attachment and the channel are configured to receivethe fastener therethrough and couple the second nearest neighborattachment and the third nearest neighbor attachment to the vane.
 2. Thevariable vane stabilizer according to claim 1, wherein the vane steminterface comprises: an axial keyed channel extending through a portionof the variable vane stabilizer and configured to receive a firstportion of the vane; keying tangs comprising bosses extending inwardlytoward a center of the axial keyed channel and configured to pressagainst a second portion of the vane; and an expansion chamfercomprising a relief undercut between the keying tangs and a radiallyoutermost face of the axial keyed channel.
 3. The variable vanestabilizer according to claim 1, wherein the second nearest neighborattachment further comprises a preload spacer radially outward of thefastener channel.